DESCRIPTION, OVERALL (provided by applicant): It is estimated that up to 50,000 children are newly diagnosed annually in the United States with vesicoureteral reflux (VUR) after a urinary tract infection. It is known that in some of these children, VUR is associated with recurrent infection, pyelonephritis and subsequent renal scarring. This can lead to hypertension and renal insufficiency later on in childhood or in adult life. There remains great confusion, however, regarding the optimal treatment of these children or indeed, if they all require treatment. While it appears that children with the higher grades of dilating reflux (grades IV &V) are at the greatest risk for clinical sequelae, they are a minority of patients. 90% of children have grades I, II or III reflux. The majority of children with low grade reflux will outgrow their reflux before adolescence. Surgical correction of reflux in these children is less commonly required, therefore. Rates of renal scarring and recurrent urinary tract infection are also lower in these children. While long term antibiotic prophylaxis works well in preventing urinary infection, it has been proposed that it may not be necessary in this group, since rates of scarring and recurrent infection are low with low grade reflux. Recently, a new minimally invasive treatment of reflux has been developed and a material known as "Deflux" has been approved by the FDA for this purpose. This material is injected via a cystoscope around the ureteral orifice. The change in configuration of the orifice caused by this bulking agent cures the reflux. Because of its ease of use and low morbidity of application, it has been proposed that this be employed as initial therapy in the majority of children with low grade reflux. Successful treatment with Deflux might render the need for long term surveillance, either on or off antibiotics unnecessary. The optimal treatment for the majority of the thousands of children with reflux, therefore, remains unknown. Do they simply require daily antibiotics? Can they be safely observed without prophylaxis? Do they require an ambulatory cystoscopic procedure? A prospective randomized study is proposed to answer this question in girls, aged one to five years with grades II or III reflux, diagnosed after a urinary tract infection. The three major treatment groups would be antibiotic prophylaxis, observation without prophylaxis, or endoscopic therapy with Deflux (ET). The clinical endpoints measured would be recurrent febrile or non-febrile urinary infections and renal scarrin